At first I expected a novel about the dead coming back to wreak havoc on those who've betrayed and harmed them in life, but deeper into it, I realized it was more about how the ghosts are fueled by the inner guilt of the living, taking shape to either warn, or remind, them of what's waiting around the corner. Focusing on two couples who are brought together by a young waif-ish yet beautiful medium, Oona, the novel is told in their perspective - quite personal and not meandering into atmosphere, dramatic plot contrivances, but staying within nuance and suggestion - reality. These characters are not really likable, but they have dimension, truths, and Tessier lets all their dark secrets unfold with a masterly and patient aim. While it is an 'understated' horror novel (no paramount dualities of good versus evil here), Tessier goes quite brutal in scenes, and the last quarter of the book reads like a gruesome tragedy of fate. Elegant at times, visceral when it needs to be, Fog Heart is a unique, stand-out novel of horror.
(note: I imagined German/Irish actor, Michael Fassbender, playing the role of the Brit, Oliver - and at the end of the novel, thought that Fassbender's collaborator, director Steve McQueen, would be a perfect choice to visualize this novel).